1. Background Field
The present invention relates generally to generating databases of access points for use with localization and more particular, to improving the accuracy of estimated locations of access points in databases.
2. Relevant Background
Access point databases provide a useful resource for localization, particularly in areas where satellite signals for positioning are scarce, e.g., when indoors or in urban canyons, or when a fast time-to-first fix is desired. Access points are wireless devices through which networks may be accessed by mobile devices or other wireless devices. Mobile devices can detect one or more access points in their proximity and refer to the access point database to estimate a position of the mobile device.
Typically, the positions of access points in access point databases are not very precise, which adversely effects the estimated position of mobile devices when relying on the access point database. For example, many access point databases are generated through wardriving or crowdsourcing in which wireless signals from an access point are measured at a plurality of known positions. Using the wireless signal measurements and the associated position fixes of the measuring device, the position of the access point may be estimated. The position fixes of the measuring device associated with the wireless signal measurements are typically generated using, e.g., satellite positioning signals (SPS), such as the Global Positioning System (GPS). Consequently, the resulting estimated positions for the access points are often determined to be in locations where SPS position fixes are available, e.g., in outdoor locations. In turn, when relying on the access point database for localization, the estimated position of a mobile device is often determined to be in an outdoor location. Thus, it is desirable to improve the accuracy of access point databases.